This invention relates to an improved exercise device for one person which will exercise opposing muscle groups sequentially, and is available for year-round use. This multi-functional device is capable of being used in both terrestrial and aquatic environments. The aquatic environment is particularly advantageous when the user requires a low-impact workout, such as would be the case when physical therapy may be prescribed to rehabilitate a muscle group, or a set of muscle groups.
Traditional exercise equipment typically exercises only one set of muscles during utilization of the apparatus. This is illustrated by the use of resilient "rubber-band" like exercisers. This approach is effective in exercising a given set of muscles, such as the chest muscle group (e.g. pectoralis major) when grasping the device by the hands, but is not useful in exercising the opposing back muscle set (e.g. infraspinatus, teres minor, teres major, and rhomboideus major), in this example.
Since physical exertion occurs only when elongating the device, the period of time during which the device is returning to its normal "relaxed" state, is non-productive from an exercise standpoint, unless the participant uses force to prevent the rapid natural contraction of the device. Even when this is done, the exertion only benefits the contracted set of muscles. The opposing muscles, which can be exercised only by performing an operation requiring exertion in an opposite direction, such as an exertion requiring compression, are not used.
One approach to alternately exercising different sets of muscles is illustrated in U.S. Pat. No. 4,830,366. In this configuration, a central accordion-like compression member is linked via a nut and bolt configuration, to elastic tension members which provide resistance to an elongation force. The user straps the device to a pair of limbs using an inelastic strap with bayonet-type clasps.